This invention is directed to a system and method for establishing alignment of an automated movable operating member with an article that is processed by the movable operating member, and more particularly to a robot alignment system and method for aligning a robot operating member with an article that is automatically processed by the robot.
Robots have long been used to perform processing operations that were previously performed manually, such as painting, polishing, soldering, assembling, machining and mixing, to name a few. A robot can include one or more manipulative members such as robot arms, which are generally referred to herein as robot operating members. Robots are also used to transport articles from one location to another and/or perform processing operations other than those previously indicated.
The term “processing” as used herein is intended to refer to any type of operation performed by a robot on or with an article. Also, the term “robot” may be used interchangeably herein with the term “robot operating member.”
U.S. Pat. No. 6,293,750 shows a blood sample analysis system that incorporates at least one robot to retrieve and transport containers such as sample tubes from one location to another for a variety of processing operations. The robot is movably supported on an overhead horizontal beam for back and forth movement, rotational movement about a vertical axis, and up and down movement along the vertical axis.
In other known robot systems a robot can be movably supported on a platform or base, for performing a predetermined operation. Generally, in most currently used robot systems, whether the robot is supported overhead or on a platform or base, the movement of the robot is usually automatically controlled by a programmable computerized control system.
Thus, using known programming techniques, a robot control system can be programmed to provide automated movement of the robot to one or more selected locations in a predetermined sequence to perform one or more processing operations. For example, in the robot system of U.S. Pat. No. 6,293,750 the robot moves automatically to a first location to pick up a sample tube, transports the sample tube to a second location, releases the sample tube at the second location and returns to the first location to repeat the pickup and delivery operation.
Programming of the movement and function of a robot, such as the robot of U.S. Pat. No. 6,293,750, to move to one or more selected locations to perform a pick up and/or delivery operation often requires that a precise alignment position be established between the robot and the article that is processed by the robot. Thus the robot must be precisely aligned with the article that is to be processed before the robot can begin to perform the processing operation. The robot must also be precisely aligned with a desired delivery location before the robot releases the article at the delivery location.
Therefore, during programming of a robot control system, the precise location of a pickup and delivery position for example, and any other necessary positional information is communicated to the robot control system so that the control system can accurately govern repetitive automated movement of the robot to selected pick-up and delivery positions.
For example, once a sample tube pick-up position and a sample tube delivery or drop-off position are established and communicated to the robot control system, the control system can be programmed to automatically move the robot to the selected pick-up and delivery positions to perform the desired processing operations.
In some instances the robot and the article being processed are each separately moved to an alignment position. In other instances the article that will be processed by the robot does not move independently of the robot. The robot thus moves to an alignment position with the article, before the article is processed by the robot. The actual processing operation is also usually controlled by the robot control system.
One known method of establishing alignment between a robot and an article that is processed by the robot includes providing the robot with a first alignment pin (the robot pin) and providing the article being processed with a second alignment pin (the article pin). The robot pin and the article pin generally have the same directional orientation such as vertical, horizontal, or inclined, for example. The robot is moved, in any suitable known manner, to a selected alignment position wherein the robot pin aligns with the article pin. Alignment is usually established when a programming operator makes a visual determination that the robot pin and the article pin are in alignment.
The programming operator then communicates the alignment position to the robot control system, in any suitable known manner, to thereby program the alignment information in the robot control system. The robot control system is thus programmed to automatically move the robot to the selected alignment position to begin processing of the article. Other alignment positions can be programmed in similar fashion in the robot control system to govern further movement and functional operations of the robot on articles being processed by the robot.
During programming of alignment positions in a robot control system, it has been found that visual recognition of alignment between a robot pin and an article pin can be inaccurate. Such inaccuracy can occur because of depth perception problems of an operator, as well as other problems of visual acuity that an operator may have. Visual problems of an operator as well as human error in establishing an alignment position are further compounded when space limitation problems prevent an operator from being close enough to a robot system to clearly discern when there is alignment between the robot pin and the article pin.
It is thus desirable to provide an alignment system and method for establishing a predetermined alignment position between a movable operating member and an article processed by the operating member, wherein the alignment system does not rely on visual acuity of a programming operator.